TSA screenings at airports too invasive? 'Opt Out' protest planned.

When the machines were introduced at London’s Heathrow Airport earlier this year, the first sexual harassment suit resulted within two months, reported the BBC. A young woman spoke to the police after the guard commented on her breasts after seeing her scan. The angry and embarrassed woman said she felt traumatized by the incident.

But the machines enhance security in the post-9/11 world, administration officials say, and procedures are in place to avoid instances such as the Heathrow one.

"AIT machines are safe, efficient, and protect passenger privacy," wrote Janet Napolitano, head of the Department of Homeland Security, in a Nov. 15 op-ed in USA Today. "And the weapons and other dangerous and prohibited items we've found during AIT screenings have illustrated their security value time and again. Rigorous privacy safeguards are also in place to protect the traveling public.... The officer assisting the passenger never sees the image, and the officer viewing the image never interacts with the passenger."